Jeremiah,first i,m a retired machinist ,and as a hobby i restore cubs and others ,.my first cub i rebuilt did have the knock .and the next one i set out to see why ,so i set the cam up in the lathe and found each end was off as much as .008 and other end was off as much as .005 so i machined both ends true ,and as for the end side of the block it was off as well ,so i made a lapping tool and lapped them both true .and made new shims to pick up the clearance to give it .007 on both the cam and crank .i try too keep them the same because if you don,t one will clime the other ,and there is the knock ,this was the last knock i ever had ,and i have rebuilt many of the K engines ,and there is not much else true about thease engines either ,i do have photos of what i have done ,but sorry i can,t send them .because i have the new 8.1 p/c and its more than i can handle to sent photos .i hope any of this helps .David